Change default OTLP/HTTP port number

This implements specification change open-telemetry/opentelemetry-specification#1839

To make transition to new port numbers less painful OTLP receiver will
also accept data on the legacy port numbers when it is configured to
use the default endpoint. Users who use the default Collector config
can continue sending data to the legacy ports and have a graceful period
to update their senders to start sending to the new ports.

Author: tigrannajaryan

receiver/otlpreceiver/README.md

@@ -25,7 +25,7 @@ receivers:
 
 The following settings are configurable:
 
-- `endpoint` (default = 0.0.0.0:4317 for grpc protocol, 0.0.0.0:55681 http protocol):
+- `endpoint` (default = 0.0.0.0:4317 for grpc protocol, 0.0.0.0:4318 http protocol):
   host:port to which the receiver is going to receive data. The valid syntax is
   described at https://github.com/grpc/grpc/blob/master/doc/naming.md.
 
@@ -46,7 +46,7 @@ serialization](https://developers.google.com/protocol-buffers/docs/proto3#json).
 
 To write traces with HTTP/JSON, `POST` to `[address]/v1/traces` for traces,
 to `[address]/v1/metrics` for metrics, to `[address]/v1/logs` for logs. The default
-port is `55681`.
+port is `4318`.
 
 The HTTP/JSON endpoint can also optionally configure
 [CORS](https://fetch.spec.whatwg.org/#cors-protocol), which is enabled by
@@ -58,7 +58,7 @@ receivers:
   otlp:
     protocols:
       http:
-        endpoint: "localhost:55681"
+        endpoint: "localhost:4318"
         cors_allowed_origins:
         - http://test.com
         # Origins can have wildcards with *, use * by itself to match any origin.

receiver/otlpreceiver/config_test.go

@@ -139,7 +139,7 @@ func TestLoadConfig(t *testing.T) {
 					ReadBufferSize: 512 * 1024,
 				},
 				HTTP: &confighttp.HTTPServerSettings{
-					Endpoint: "0.0.0.0:55681",
+					Endpoint: "0.0.0.0:4318",
 					TLSSetting: &configtls.TLSServerSetting{
 						TLSSetting: configtls.TLSSetting{
 							CertFile: "test.crt",
@@ -155,7 +155,7 @@ func TestLoadConfig(t *testing.T) {
 			ReceiverSettings: config.NewReceiverSettings(config.NewIDWithName(typeStr, "cors")),
 			Protocols: Protocols{
 				HTTP: &confighttp.HTTPServerSettings{
-					Endpoint:    "0.0.0.0:55681",
+					Endpoint:    "0.0.0.0:4318",
 					CorsOrigins: []string{"https://*.test.com", "https://test.com"},
 				},
 			},
@@ -166,7 +166,7 @@ func TestLoadConfig(t *testing.T) {
 			ReceiverSettings: config.NewReceiverSettings(config.NewIDWithName(typeStr, "corsheader")),
 			Protocols: Protocols{
 				HTTP: &confighttp.HTTPServerSettings{
-					Endpoint:    "0.0.0.0:55681",
+					Endpoint:    "0.0.0.0:4318",
 					CorsOrigins: []string{"https://*.test.com", "https://test.com"},
 					CorsHeaders: []string{"ExampleHeader"},
 				},

receiver/otlpreceiver/factory.go

@@ -31,8 +31,9 @@ const (
 	typeStr = "otlp"
 
 	defaultGRPCEndpoint = "0.0.0.0:4317"
-	defaultHTTPEndpoint = "0.0.0.0:55681"
+	defaultHTTPEndpoint = "0.0.0.0:4318"
 	legacyGRPCEndpoint  = "0.0.0.0:55680"
+	legacyHTTPEndpoint  = "0.0.0.0:55681"
 )
 
 // NewFactory creates a new OTLP receiver factory.

receiver/otlpreceiver/otlp.go

@@ -155,6 +155,18 @@ func (r *otlpReceiver) startProtocolServers(host component.Host) error {
 		if err != nil {
 			return err
 		}
+		if r.cfg.HTTP.Endpoint == defaultHTTPEndpoint {
+			r.logger.Info("Setting up a second HTTP listener on legacy endpoint " + legacyHTTPEndpoint)
+
+			// Copy the config.
+			cfgLegacyHTTP := r.cfg.HTTP
+			// And use the legacy endpoint.
+			cfgLegacyHTTP.Endpoint = legacyHTTPEndpoint
+			err = r.startHTTPServer(cfgLegacyHTTP, host)
+			if err != nil {
+				return err
+			}
+		}
 	}
 
 	return err